1. Field of the Invention
The present invention relates to a recoil starter to be employed for starting an internal combustion engine which is adapted to be mounted on a backpack-type power working machine such as a backpack-type power blower (air blower-type cleaner), backpack-type power sprayer, etc.
2. Description of the Related Art
The recoil starter to be employed for starting an internal combustion engine which is adapted to be mounted on a backpack-type power working machine is generally constructed such that it is provided with a recoil handle (recoil rope) so that the internal combustion engine can be started by pulling the recoil handle against the compression-resisting force of the engine, and that once this recoil handle is released, the recoil rope is automatically wound up to the original state thereof by the effect of recoil-urging means.
When the recoil rope is kept wound up to the original state thereof, i.e. when the engine-starting operation is not performed, the recoil handle is usually kept stayed at the recoil rope outlet port of the main body of the starter. Therefore, it is impossible for the operator to reach the recoil handle under the condition where the working machine is kept shouldered by the operator""s back, i.e. it is impossible for the operator to pull the recoil handle and hence to start the internal combustion engine under such a condition as mentioned above. Therefore, if the operator wishes to restart the internal combustion engine after the stop thereof while carrying the working machine on his back, the working machine is required to be once dismounted from his back, which action is quite inconvenient for the operator.
Whereas, when a D.C.-motor type starter is employed as a starter, the internal combustion engine can be easily started while carrying the working machine on the operator""s back. In that case however, the total weight of the working machine would be considerably increased due to the D.C.-motor and the battery as a power source for the D.C.-motor, and at the same time, the structure of the starter would become complicated, thus increasing the manufacturing cost thereof.
Under the circumstances, there has been proposed a recoil starter which makes it possible to perform the starting operation of the internal combustion engine under the condition where the backpack-type power working machine is kept shouldered by the operator""s back. For example, Japanese Utility Model Unexamined Publication S59-19975 discloses a recoil starter wherein the recoil rope is designed to be guided by a flexible guide pipe. Since this recoil starter is constructed such that the recoil handle thereof (recoil rope and one end of the guide pipe) is not supported at all, it is difficult to smoothly perform the rope-pulling operation. Moreover, since the recoil rope and the guide pipe end are allowed to hang loose during the working operation, there are problems that they may disturb the working operation or may be damaged as they are caught by the branch of a tree.
On the other hand, Japanese Utility Model Publication H2-48695 discloses a recoil starter wherein a base end portion of the guide pipe for guiding the recoil rope is supported by the main body of the starter, and a distal end portion of the guide pipe is secured to the shoulder contact portion of the shouldering band. According to this recoil starter, since the recoil handle (grip) is supported at the vicinity of a front portion of the shoulder (or a distal end portion of the guide pipe), the recoil handle can be prevented from being hung loose. However, there are problems that the face of the operator may be impinged against the recoil handle, and that the guide pipe may bend as it is caught by the branch of a tree, thus damaging the guide pipe, in particular, the base end portion thereof.
The present invention has been made in view of overcoming the aforementioned problems accompanied with the conventional starters, and therefore, it is an object of the present invention to provide a starter for a backpack-type power working machine, which is capable of easily performing the starting operation of an internal combustion engine under the condition where the working machine is kept carried on the operator""s back, which can be manufactured lighter in weight and cheaper in manufacturing cost, which is relatively free from trouble, and which can hardly be damaged even if a portion of the starter is caught by the branch of a tree.
With a view to attaining the aforementioned object, there is provided, in accordance with the present invention, a recoil starter for starting an internal combustion engine to be mounted on a backpack-type power working machine. The recoil starter comprises a recoil rope; a recoil handle which is attached to one end portion of said recoil rope, placed remote from the main body of the starter by a predetermined distance, and adapted to be supported by a handle-supporting member provided at a specific portion of said backpack-type power working machine; and a flexible guide pipe loosely sheathing an extended portion of said recoil rope which is located between said main body and said handle-supporting member, one end of said guide pipe being fixed, and the other end thereof being made free.
Preferably, said handle-supporting member is provided at a portion of the working machine, which approximately corresponds to the waist portion of the operator shouldering the working machine, thereby enabling the recoil handle to be pulled toward the front of the operator on the occasion of starting the internal combustion engine.
Preferably, said guide pipe is made of a synthetic resin, and one end of said guide pipe is press-inserted into a cylindrical portion provided at said handle-supporting member, thereby enabling said guide pipe to be detachably secured to the handle-supporting member. More preferably, an elastic ring member is externally fitted on one end portion of the guide pipe which is located close to the main body.
The recoil starter for a backpack-type power working machine according to the present invention, which is constructed as described above, is characterized in that the recoil handle is placed remote from the main body of the starter by a predetermined distance and supported by the handle-supporting member provided at a specific portion of the backpack-type power working machine (for example, a portion corresponding to a right waist portion of the operator), that the recoil handle is designed to be pulled toward the front of the operator, that a flexible guide pipe is provided so as to loosely sheath an extended portion of the recoil rope which is located between the main body and the handle-supporting member, and that one end of the guide pipe is fixed and the other end thereof is made free. Therefore, the starting operation of the engine can be easily performed even under the condition where the working machine is kept shouldered by the operator. Additionally, since this recoil starter for a backpack-type power working machine according to the present invention is the same in structure as the conventional recoil starter for a backpack-type power working machine except that only the handle-supporting member and the flexible guide pipe are additionally provided, the recoil starter can be made lighter in weight and lower in manufacturing cost as compared with a D.C.-motor type recoil starter.
Further, since the recoil starter according to the present invention is simple in structure, it is possible to minimize the breakdown thereof. Additionally, even if the flexible guide pipe is caught by the branch of a tree, the guide pipe can be bent in the direction pulled by the branch of the tree, and at the same time, the recoil rope is permitted to be drawn out of the main body of the starter (from the reel thereof), thus enabling the free end side of the recoil rope to move in the direction pulled by the branch of the tree, so that the fixed end portion of the guide pipe can be prevented from being imposed by a large magnitude of load, and therefore can be inhibited from being damaged.
On the other hand, since the recoil starter for a backpack-type power working machine of the present invention is designed such that the engine-starting operation is performed while shouldering the working machine, it is preferable to employ a recoil starter which enables the start-up of the engine to be performed with a relatively small magnitude of rope-pulling force as compared with a recoil starter where the rope-pulling operation is performed after dismounting the working machine.
As for the recoil starter which enables the start-up of the engine to be performed with a relatively small magnitude of rope-pulling force, a power-accumulating type recoil starter has been previously proposed by the present inventors. This power-accumulating type recoil starter comprises a driving member which can be rotated by the pulling of the recoil rope, a driven member to which the rotation of the driving member is designed to be transmitted, and a buffering/power-accumulating means which is disposed between the driving member and the driven member, wherein the buffering/power-accumulating means is enabled, during the driving process by the driving member, to accumulate the power supplied through the driving process while alleviating any shock to the driven member, the accumulated power being subsequently employed to drive the driven member (for more details, see Japanese Patent Unexamined Publication 2001-132591, and its U.S. patent application equivalent, Ser. No. 09/639,561, which are incorporated herein by reference).
According to this power-accumulating type recoil starter, since the buffering/power-accumulating means (a spiral spring mechanism) is interposed between the driving member and the driven member, it is possible to derive a buffering effect from the spiral spring mechanism during the first-half driving process (until the piston of the internal combustion engine reaches the top dead center thereof) in the pulling operation of the recoil rope (recoiling operation), and at the same time, to enable the pulling force of the recoil rope to be accumulated in the spiral spring mechanism. During the latter-half driving process, the pulling force thus accumulated in the spiral spring mechanism during the first-half driving process is permitted to be combined with the pulling force to be actually effected in the latter-half pulling operation of the recoil rope to thereby generate a resultant force, which is utilized as a force for starting the internal combustion engine. As a result, it is possible to minimize a fluctuation in pulling force of rope so as to smooth the rope-pulling operation, and also to enable the engine to be easily started while the working machine is kept shouldered on the operator""s back without requiring a large magnitude of pulling force.